Electric drill.



PATENTED JAN. 23, 1906.

C. W. THBIL. ELECTRIC DRILL. APPLICATION FILED JUNE 1.1903.

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NTTED sTATEs PATENT oEEIcE.

CHARLES W. THEIL, OF MILWAUKEE, WISCONSIN, ASSIGNOR OF ONE-THIRD TOALONZO D. SEAMAN AND ONE-THIRD TO JOHN T. SEAMAN, OF MIL- WAUKEE,WISCONSIN.

ELECTRIC DRILL.

Specification of Letters Patent.

Patented Jan. 23, 1906.

To all whom it may concerm' Be it known that I, CHARLES W. THEIL, acitizen of the United States, residing at Milwaukee, in the county ofMilwaukee and State of Wisconsin, have invented certain new and usefulImprovements in Electric Drills, of which the following is aspecification, reference being had to the accompanying drawings, forminga part thereof.

This invention relates to portable owerdrills. Its main objects are topro uce a light, powerful, compact, and self-contained electric drillwith few and simple parts and generally to improve the construction andoperation of drills of this class.

It consists in certain novel features of construction and in thepeculiar arrangement and combinations of parts hereinafter particularlydescribed, and pointed out in the claims.

In the accompanying drawings like letters designate the same parts inboth figures.

Figure l is a medial lon itudinal section of an electric breast-drillern odying my invention; and Fig. 2 is a cross-section of the same onthe line 2 2, Fig. 1.

The case or frame of the drill is composed of coaxial sectionscomprising an end bearing and breast-piece a, a motor field-piece b, aninternal gear and bearing piece c, connected withthe motor field-pieceby distance-piece d, and an end-thrust bearing-piece e, which forms,with the internal gear c, a gear-case. These sections are bolted orscrewed together, as shown, and their coaxial or central relation toeach other is insured by interfitting circular recesses and projectionson adjoining parts. The end bearing and breast-piece-a is enlarged andmade hollow at the end next to the field-piece b to form a housing f forthe commutator and brushes ofthe motor. The field-piece b is providedwith suitable coils g.

h is the motor-armature, the shaft i of which has bearings in thebreast-piece a and in the hub of the gear c and is provided in thehousing f with a commutator j. The brushes c 7c are supported in theproper relation to the commutator by rods or binding-posts Z l,Whichvare adjustably secured and insulated in the outer end of thehousing f, parallel with the armature-shaft. The bore in the breastpiecea is extended through the outer end thereof and closed with a screw-plugm to form an oil-receptacle for lubricating the adjacentarmature-bearing.

n is a rotary drill` chuck or holder formed or provided with an internalgear o, the pitchcircle of which preferably corresponds with that of thefixed gear c, but which has more or less teeth than said fixed gear.

An end-thrust ball-bearing p is preferably interposed between the endpiece e of the case or frame and an outwardly-projecting flange orshoulder on the drill chuck or holder,which also has a central bearingon the end of the armature-shaft i, which projects through and beyondthe fixed gear c.

Between the internal gears c and 0 a double crank g is fixed on thearmature-shaft and is provided on one side thereof with a pinion 1',meshing with both internal gears and on the other side with acounterweight s. The end piece e of the case or frame is provided onopposite sides with handles t for guiding and holding the drill. Aswitch u for stopping and starting the motor may be conveniently locatedon the breast-piece a, as shown in Fig. 1.

The relative number of teeth of the differential internal ears c and 0may be varied according to conditions and requirements.

The machine herein shown and described operates as follows: A drill vbeing inserted in the chuck or holder n, as shown in Fig. 1, and themotor being started by closin the switch u, the crank g will be rotatedwit the armature h, carrying the pinion r around the shaft i or axis ofthe drill in en agement with the fixed and movable internaIgears c ando, and thereby rotating the pinion in the opposite direction. Assumingthat the fixed gear c has thirty teeth, as shown in Fig. 2, andv thatthe movable gear o has thirty-three teeth, or one-tenth more than thegear c, the gear o will be advanced one-tenth of a revolution withrelation to the fixed gear c to each revolution of the crank, or themovable ear o, with the drill-holder n and drill v, wil be turned onerevolution to every tenl revolutions of the armature and in the samedirection. The relative speed of the drill-holder and armature may bevaried as desired by varyin the relative number of teeth of the internagears, and the rotation of the drill IOC may be reversed withrelation tothe rotation of the armature by providing the fixed gear c with moreteeth than the movable gear o.

Various changes in the minor details of construction and arrangement ofparts may be made without materially affecting the operation of thedrill and without departing Jfrom the principle and intended scope oi myinvention.

I claim- 1. In an electric drill the combination with a suitable case orframe, of a motor-armature and a rotary drill-holder mounted coaxiallytherein, differential internal gears,.iixed one to the drill-holder andthe other to said case or frame, and a crank fixed to the armatureshaftand provided with a pinion which meshes with both of said internalgears, said drill-holder being rotatable and the case stationaryrelatively to each other and the armature-shaft, substantially asdescribed.

2. In an electric drill the combination with a suitable case of amotor-armature and a rotary drill-holder mounted coaxially therein,differential internal gears fixed one to the drill-holder and the otherto the case or frame, said drill-holder being rotatable and the casestationary relatively to each other and the armature-shaft, and a crankiixed to the armature-shaft and provided on one side thereof with apinion which meshes with both internal gears and on the other side witha counterweight, whereby motion is transmitted from the armature-shaftto the drillholder through said pinion and dierential gears,substantially as described.

3. In an electric drill the combination of a case or Jframe composed ofcoaxial sections comprising a motor field-piece, a fixed internal gearand end bearing-pieces, a drill-holder provided with an internal gearhaving a different number of teeth from the xed gear, and amotor-armature provided with an eccentrically-mounted pinion meshingwith both internal gears, said drill-holder being rotatable and the casestationary relatively 4. In an electric drill the combination with acase or frame provided with coaxial bearings, with a fixed internal gearand with a motor-field, of a motor-armature mounted in said bearings andprovided with an eccentrically-mounted pinion meshing with said internalgear, and a rotary drill-holder having a central bearing on thearmature-shaft, an end-thrust bearing on the case or frame and aninternal gear meshing with said pinion, one of said gears having adifferent number of teeth from the other, and said drill-holder beingrotatable and the case stationary relatively to each other and thearmature-shaft, whereby motion is transmitted to the drillholder fromthe motorarmature through said pinion and differential gears,substantially as described.

5. In an electric drill the combination of a case or frame composed ofcoaxial sections comprising a motor-iield, a iixed internal gear and endpieces, of a motor-armature having bearings in said case or frame, andprovided with an eccentrically-mounted pinion meshing with said gear,and a drill-holder having an end-thrust ball-bearing between it and saidcase or Jframe and an internal gear meshing with said pinion, one ofsaid gears having a diiierent number of teeth from the other, and saiddrill-holder bein(T rotatable andthe case stationary relatively to cachother and the armature-shaft, whereby motion is transmitted to thedrill-holder Jfrom the motor-armature through said pinion anddifferential gears, substantially as described.

In witness whereofl hereto affix my signature in presence of twowitnesses.

CHARLES w. THEiL.

Witnesses:

CHAs. L. Goss, ANNIE SEIDEL.

